JPH06219598A - Image former - Google Patents

Abstract

PURPOSE:To make a paper jam easily dissolvable even if a conveying failure occurs to a recorded material by installing a space part for feeding in this recorded material at the time of abnormal recording operations, in a part of a conveyor means made takable out of a device body. CONSTITUTION:When a paper jam has occurred, those of paired conveyor rollers 45C, 46A, 47A, 47B at the upstream side in the recording paper conveying direction are made so as to be rotated as long as the specified time by a register roller pair 44 after a transfer drum 5 and this register roller pair 44 are stopped. Therefore, succeeding recording paper P2 gets slackening in an interval between the register roller pair 44 and the paired conveyor rollers 47A, 47B, and a conveyor guide 48D is largely turned round by means of paper stiffness whereby a space part S2 larger than an ordinary space part S1 is formed up therein, and the paper P2 is stopped in a state of being largely curved to the space part S2. So, a user opens a front door of the device body, drawing out a transfer conveyor unit 50A to somewhere short of this side, and thus the recording paper P2 conveyed next to the jam paper P1 is easily removable in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine or a facsimile which employs an electrophotographic system or an inkjet system.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a facsimile, there is known an apparatus which forms an image by an electrophotographic system or an inkjet system while conveying a recording material such as recording paper. A copying machine adopting the electrophotographic method will be described below with reference to FIG. The apparatus is roughly divided into an image input section 90R and an image output section 90P. The image input unit 90R inputs image information to be recorded, performs various processes, and then outputs the image output unit 90P.
This is a device for transferring the image signal of the navel. Further, the image output section 90P is an image forming section 91 for forming a recorded image in accordance with the image signal, a sheet feeding unit 92 for stacking a plurality of recording sheets P and feeding the sheets one by one, and the sheet feeding unit 92. A transfer conveyance unit 93 for conveying the recording paper P sent from the unit 92 to the image forming unit 91 while holding it, and a transfer conveyance unit 93 for transferring the image onto the recording paper P, and a fixing for fixing the image recorded on the recording paper. It consists of a unit 94 and a control unit 95 for controlling all operations in these devices.

The recording operation of the copying machine will be described. When the recording operation is started, first, one sheet of recording paper P is fed from the paper feeding unit 92 and temporarily stopped in front of the transfer / transport unit 93. The sheet is conveyed to the registration roller 96, and the skew is corrected. After that, the registration rollers 96 rotate in synchronization with the image recording start signal, and send the recording paper P onto the transfer / transport unit 93 (this operation allows an image to be formed at a predetermined position on the recording paper P). . The recording paper P is conveyed to the image transfer area while being held on the transfer conveyance unit 93, and the image formed by the image forming section 91 is transferred and recorded on the recording paper surface.

Here, a transfer / conveyance unit for the recording paper P.
As a holding method on 93, several methods such as electrostatic adsorption on a carrier medium made of a thin dielectric film or air adsorption can be considered. When transfer recording is performed on the recording paper P, the transfer conveyance unit 93 conveys the recording paper P to the vicinity of the fixing unit 94, and sends the recording paper P to the fixing unit 94 while separating the leading end thereof. In the fixing unit 94, heat and / or pressure is applied to fix the transferred image on the recording paper P, and then the recording paper P passes through the paper discharge unit and is output to a discharge tray provided outside the apparatus.
The paper is ejected on 97.

It is conceivable that a recording paper conveyance failure may occur during the above recording operation. In that case, the recording operation is interrupted, an abnormality in the conveyance is displayed on the display device, and the user of the apparatus takes a corresponding action such as removing the paper. Will be taken (hereinafter referred to as "jamming"). In this case, what is important as a device is
This is to make it easy for the user to clear the jam, and to prevent the recording paper that should be removed during the jam processing from being torn and remaining in the device or damaging the parts inside the device. Is preferably provided.

It is conceivable that the transfer / conveyance unit 93 has a complicated structure and that the frequency of occurrence of jam is higher than that of other portions. Therefore, in order to perform the jam processing in the transfer / conveyance unit 93 easily, reliably, and safely, generally, the following configuration is often adopted. That is, the transfer / transport unit 93 (the portion surrounded by the chain double-dashed line in FIG. 9) can be drawn out from the inside of the apparatus to the front side (the direction vertical to the drawing), and after the user once pulls out the transfer / transport unit 93. The recording paper P adsorbed on the unit is peeled off from the conveying medium. According to the jam processing method, as compared with the case where the user inserts his / her hand into the apparatus to perform processing,
Since the space around the unit is largely released, the recording paper P to be removed can be easily recognized and processed. Further, there is almost no risk of deforming or damaging the carrier medium such as a thin film that attracts the recording paper P.

[0007]

However, in the copying machine shown in the above-mentioned prior art, the frequency of jam occurrence is generally high in the following parts. For example, when the recording paper P is adsorbed on the adsorption film of the transfer / conveyance unit 93 while being sent out from the registration roller 96 and the adsorbing force is insufficient for some reason, the leading end of the recording paper P immediately after the transfer area is on the image forming side. There is a possibility to plunge into the (transfer portion jam). Further, when the recording paper P is separated from the transfer / conveyance unit 93, the recording paper P is not separated because the separation operation is incomplete (separation jam), or the recording paper P that has passed through the fixing unit 94.
However, there is a possibility that the paper may not be ejected (paper ejection jam) because the leading edge of the paper is caught in the guide connecting portion due to curling in the paper ejection portion due to heat.

When the above-mentioned malfunction is detected, the conveyance operation of the recording paper P must be stopped immediately so that the jammed paper can be removed as easily as possible in order to prevent damage to the apparatus. However, if the jam processing is performed from this state, the following problems occur. That is, when the transfer / conveyance unit 93 is immediately pulled out, if jam paper is present, the recording paper P fed thereafter is stopped across both the transfer / conveyance unit 93 and the unit (conveyor unit, etc.) in the apparatus main body. If
The paper may be torn or the adsorption film may be deformed or damaged. In order to prevent this, it is necessary to remove the paper held across both units, but the effectiveness of performing the jam processing by pulling out the transfer / transport unit 93 described above cannot be exhibited, and the jam processing is complicated. There was a fear. Further, if it is assumed that all jams of the recording paper are to be conveyed, and a jam handling mechanism corresponding to each of them is provided, the device becomes large and complicated, and the manufacturing cost increases.
Jam processing also becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an image forming apparatus capable of easily, reliably and safely performing jam processing even if a recording material is poorly conveyed.

[0010]

A typical image forming apparatus according to the present invention, which achieves the above object and is applied to the embodiments described below, has a feeding means for feeding a recording material. ,
Conveying means for conveying the recording material fed by the feeding means, registration means for correcting skew of the recording material, and conveying in synchronization with the recorded image, and image Image forming means for forming an image on the recording material according to information, and recording material carrying and conveying means for carrying the recording material and conveying it to the image forming means. The unit and the recording material carrying and conveying unit are unitized so that they can be taken out from the apparatus main body.
A part of the conveying means is provided with a second space portion for feeding the recording material during an abnormal recording operation, in addition to the first space portion necessary for conveying the recording material in the normal recording operation.

[0011]

According to the above means, the conveying means, the resist means,
Also, the recording material carrying and conveying means is unitized so that it can be taken out from the apparatus main body, and a part of the conveying means is provided at the time of an abnormal recording operation in addition to the first space necessary for conveying the recording material in the normal recording operation. By providing the second space portion for feeding the recording material, the recording material is conveyed to the second space portion when the recording operation is abnormal (for example, when the recording material is jammed). After that, the unit in which the conveying means, the resist means, and the recording material carrying and conveying means are integrated can be pulled out from the apparatus main body to perform the jam processing.

[0012]

【Example】

[First Embodiment] Next, an image forming apparatus according to a first embodiment of the present invention will be described with reference to the drawings. In this embodiment, a copying machine is used as an image forming apparatus.
1 is a cross-sectional explanatory view showing a schematic structure of a copying machine, FIG. 2 is an explanatory view showing a conveying section of the copying machine, FIG. 3 is an explanatory view of a transfer drum, FIG. 4 is an explanatory view showing a structure of a transfer conveying unit, Figure 5
6A and 6B are explanatory views showing a separating operation in the transfer drum, FIG. 6 is an explanatory view showing an operation of the sheet feeding section conveying section when a separation jam occurs, and FIG. 7 is an explanatory drawing showing an operation of the fixing unit when a transfer section jam is occurring. .

First, a schematic structure of a copying machine will be described with reference to FIGS. In this embodiment, an electrophotographic method is adopted as an image forming method, and a color copying machine in which the present invention is considered to be particularly effective will be described. This copying machine has a digital color image reader section at the top and a digital color image printer section at the bottom.

{Reader Section} First, the structure of the reader section will be briefly described. In FIG. 1, a user places an original 30 on an original platen glass 31, and when the reading operation is started, exposure scanning is performed by an exposure lamp 32. To do. The reflected light image from the original 30 is formed on the full color sensor 34 by the lens 33,
Obtain a color separation image signal. This signal is subjected to various kinds of processing in a video processing unit through an amplifier circuit (not shown) and then transferred to the printer section described below.

{Printer Unit} Next, the structure of each unit of the printer unit will be described. (Image Forming Means) In FIG. 1, reference numeral 1 denotes a photosensitive drum which is an image carrier, which is rotatably driven in the direction of the arrow in the figure, which is rotatably supported at the center. Around the photosensitive drum 1, an exposure optical system 3 equipped with a pre-exposure lamp 11, a primary charger 2, a laser oscillator, etc., a potential sensor 12, a developing device 4, and an on-drum light amount detecting means 13 according to the rotation direction. The transfer drum 5 and the cleaning device 6 are arranged in this order.
The pre-exposure lamp 11 and the primary charger 2 apply a uniform amount of charge to the surface of the photosensitive drum 1. Then, the exposure optical system 3 exposes the light beam E, such as a laser beam, which is modulated according to the recording image signal, onto the photosensitive drum 1 through the polygon mirror 3A, the lens 3B, etc., thereby forming an electrostatic latent image. To do. Further, four developing devices 4Y, 4C, 4M, and 4Bk each accommodating a developing device 4 (in this embodiment, four color developers (hereinafter, referred to as "toner") of yellow, cyan, magenta, and black are arranged side by side. The electrostatic latent image is visualized by the eccentric cams 24Y, 24C, 24M, and 24Bk so that the electrostatic latent images can be moved so as to selectively come close to the photosensitive drum 1). A cleaning device 6 is provided on the downstream side of the image transfer area in the drum rotation direction, and scrapes off the toner remaining on the photosensitive drum 1 without being transferred to the recording material to clean the drum surface. Image formation is performed by repeating the above process.

(Feeding means) The paper feeding unit 40 includes a cassette 41 for accommodating the recording paper P as a recording material, a pickup roller 42 for feeding the recording paper P one by one from the cassette 41, and Paper feed rollers 43A and 43B for transporting the recording paper P sent from the pickup roller 42 to the transfer transport unit 50, transport rollers 45A, 45B and 45C, and a paper guide are provided.

(Conveying Means and Registering Means) In FIG. 2, the recording paper P fed from the paper feeding unit 40 is conveyed by guides 48A, 48B, 48C and 48 which constitute a conveying section 50A.
Transport rollers 46, 47A, 47B while being guided by D and 48E
Transported by. A pair of registration rollers 44 is a registration unit that sends the recording paper P to the transfer drum 5 described later at the timing of image formation. 48F and 48G are suction guides for guiding the recording paper P from the registration roller pair 44 to the transfer drum 5. The two-dot chain line in the figure indicates the range that can be pulled out from the apparatus body.

The transport guide 48D is supported so as to be swingable in the arrow direction as shown in FIG. This is to secure a loop space of the recording paper P which is generated when the leading end of the recording paper P is temporarily stopped by the registration roller pair 44. Further, the registration roller pair 44 can automatically release the pressure contact state between the two rollers by a mechanism (not shown). This is for facilitating pulling out the recording paper from between the rollers during the jam processing. Further 49A, 49C
Is a recording paper detection sensor for detecting the leading end of the recording paper P to be conveyed, and is attached to the entrance of the conveyance section 50A and two places immediately before the registration roller pair 44. A photo sensor or the like is used for the recording paper detection sensors 49A and 49C.

(Recording material carrying and conveying means) FIGS. 2 and 3
In the figure, 5 is a transfer drum for carrying and carrying the recording paper P carried by the registration roller pair 44. As shown in FIG. 3, the transfer drum 5 has a frame 55F in which annular members 55A at both ends are connected by a connecting member 55B.
A recording paper holding sheet film 55S (for example, PET (polyethylene terephthalate), PVdF (polyvinylidene fluoride), or the like is used) is cylindrically wound around. At the position where the recording paper P conveyed from the registration roller pair 44 enters the transfer drum 5, the suction roller 5
G is supported on the transfer drum 5 so as to be able to come into contact with and separate from it. Inside the drum sandwiching the suction roller 5G and the recording paper holding sheet film 55S, a backup member and a suction charger 5C are arranged for counteracting the pressing force of the roller. Further, as shown in FIG. 1, in the image transfer area where the photosensitive drum 1 and the transfer drum 5 face each other, a transfer charger 5B is arranged inside the drum.

As shown in FIG. 1, on the downstream side of the transfer charger 5B in the drum rotation direction, as shown in FIG. 1, a separating member for separating the recording paper P, specifically, a discharging charger 5H and a separating claw 8 are provided.
A, a film push-up roller 8B, and the like are arranged, and further, film discharging chargers 5D and 5E are arranged with the recording paper holding sheet film 55S interposed therebetween. Further on the downstream side, a brush roller 14 and a corona discharger or brush type static eliminator 15, an oil removing roller 16 and a backup for cleaning toner, paper dust and the like adhering to the recording paper holding surface of the recording paper holding sheet film 55S. A brush 17 is provided. The oil removing roller 16 removes oil used in a fixing unit described later from the recording paper P through the recording paper P during double-sided recording.

Here, the transfer drum 5 is constructed so as to be separable from and in contact with the photosensitive drum 1, and is separated apart from the normal recording operation. This is to prevent the transfer drum 5 and the photosensitive drum 1 from coming into contact with each other for a long time, and to prevent the recording paper or the like from coming into contact with the photosensitive drum 1 and damaging the surface thereof during the jam processing as described later. is there. The transfer / transport unit 50 including the transfer unit 50A and the transfer drum 5 can be pulled out from the apparatus main body to the front side by sliders 62A and 62B. This is to perform jam processing or maintenance safely, reliably and easily.

Next, the specific structure of the transfer / transport unit 50 is shown in FIG. The transfer / conveyance unit 50 is configured such that the transfer drum 5 is rotatably supported by a unit frame framed by a unit front side plate 50F, a unit rear side plate 50R, a positioning shaft 50P, a stay shaft 50S, and the like.
This unit consists of a groove 70FP on the front plate 70F and a rear plate of the device.
The positioning shaft 50P is inserted into the hole 70RP of the 70R to be positioned and supported with respect to the apparatus main body. A cam shaft 72, to which a cam 71 is fixed, is rotatably supported on the apparatus main body side, and the cam surface is close to or in contact with the stay shaft 50S (the stay shaft 50S is biased toward the cam 71 side by a mechanism not shown). Has been). A gear 73 and a spring clutch 74 for transmitting the drive from the main body of the apparatus are fixed to one end of the cam shaft 72, and the cam 71 is selectively rotated by 180 ° by a cooperation action of both (and a plunger (not shown)). It can be rotated and stopped. The stay shaft is rotated by the rotation of the cam 71.
When 50S is pressed, the transfer / transport unit 50 swings around the positioning shaft 50P. Then, in accordance with the phase at which the cam 71 is stopped, the transfer drum 5 has a position closest to the photosensitive drum 1 (hereinafter referred to as “operating position”) and a position farthest away (hereinafter referred to as “retracted position”). It is configured to take two positions.

More specifically, in the retracted position, the transfer drum 5 is positioned by a stopper (not shown), and the stay shaft 50S and the cam surface are slightly separated from each other. Therefore, at this position, the transfer drum 5 can be pulled out from the apparatus main body. On the contrary, when the transfer drum 5 is not in the retracted position, the transfer / transport unit 50 is provided with a safety mechanism (not shown) so that it cannot be pulled out from the apparatus main body. This eliminates the risk of the photosensitive drum 1 and the transfer drum 5 rubbing against each other and scratching each other when the transfer / transport unit 50 is pulled out from the apparatus main body.

(Fixing Unit) Further, in FIG. 1, the fixing unit 9 includes a fixing roller 9A having a heat source such as a halogen heater therein and a pressure roller 9B (a heat source on the pressure roller side) that is pressed by the fixing roller 9A. May be provided), a conveyor belt 9C for guiding the recording paper P to the nip portion of the roller pair, an entrance guide 9D, and a discharge for further conveying the recording paper P discharged from the roller pair to the outside of the apparatus. Equipped with a paper roller pair 9E. The recording paper P on which the image is transferred is heated and pressed when passing between the fixing roller 9A and the pressure roller 9B to fix the transferred image, and a discharge tray provided outside the apparatus by a discharge roller pair 9E. Transported to 10 and discharged.

(Double-Sided Recording Mechanism) The copying machine according to the present embodiment is constructed so that recording can be carried out on both sides of the recording paper P, and the construction for that purpose will be described below. In FIG. 1, a transport path switching guide 19 is rotatably provided immediately downstream of the fixing unit 9, and either a paper path for discharging outside the apparatus after image fixing or a paper path for double-sided recording is provided. It is configured for automatic selection. The double-sided recording paper path includes a conveyance vertical path 20, a reverse path 21A, and a reverse roller 21.
B, the intermediate tray 22 and the like, and the recording paper P which is once guided to the reversing path 21A is conveyed with the rear end side when fed by the reverse rotation of the reversing roller 21B as the leading end.
Loaded on. The recording paper P stacked on the intermediate tray 22
Are picked up one by one by the pickup roller 25, and the paper feeding unit 40 is fed by the paper feeding rollers 26A and 26B.
Then, the image is formed on both sides by the image forming means described above. Here, the guide portion 23 provided on the upper portion of the intermediate tray 22 has a plurality of guide portions 23 that selectively move up and down according to the size of the recording paper to be stored, even if the intermediate tray 22 has any size. It is configured so that the tips can be stacked with the tips aligned.

(Control Unit) Next, a control unit for controlling the operation of each unit will be described. Although not shown, the control unit is composed of a control board for controlling the operation of the mechanism in each unit, a motor drive board, and the like.
Further, the drive system of the copying machine according to the present embodiment will be described. The photosensitive drum 1 and the transfer drum 5 are driven by one motor (the photosensitive drum 1 is driven by the motor, and the gear is transferred from the photosensitive drum 1 to the transfer drum 5). The drive is transmitted through the roller. This is because a relative speed difference is not generated between the two drums). Is driven to rotate by the motor. Further, the drive is transmitted to each roller via a clutch, whereby the rotation timing can be controlled independently. However, such a configuration is not necessarily required, and it is sufficient if at least the registration roller pair 44 and the other rollers can be independently rotationally controlled. Further, the fixing unit 9 is also independently equipped with a motor, which drives the conveying belt 9C, the fixing roller pairs 9A and 9B, and the paper discharge roller pair 9E.

(Image Forming Operation) Next, an image forming operation of the printer unit configured as described above will be described. In the present embodiment, a case will be described in which the sheet is fed from the sheet feed cassette 41 in the second stage from the bottom. When the image forming operation start signal is issued, the cam 71 shown in FIG. 4 makes a half rotation, and accordingly, the transfer drum 5 swings to the operating position and rotates in synchronization with the photosensitive drum 1. At this time, the recording paper P is sent out from the cassette 41 one by one by the pickup roller 42 shown in FIG. Then, the recording paper P is guided between the paper feed guides by the paper feed rollers 43A and 43B and the conveyance roller pairs 45B and 45C, and is conveyed to the conveyance section 50A.

As shown in FIG. 2, the recording sheet P is conveyed to the registration roller pair 44 by the action of the conveying roller pairs 46A, 47A, 47B and the conveying guides 48A, 48B, 48C, 48D, 48E in the conveying section 50A. . At this time, the registration roller pair 44 is stopped, and the leading end of the recording paper P hits the nip portion to correct skew. Then, after a lapse of a fixed time (actually, a fixed time after the recording paper detection sensor 49C detects the leading edge of the recording paper), the pair of conveyance rollers 46A, 47A,
Stop driving 47B. The recording paper P conveyed within this time forms a loop with its front end abutting against the registration roller pair 44, and the space required at this time is formed by the swing of the conveyance guide 48D (recording paper P). It is automatically spread by the strain of P (see FIG. 2R)). afterwards,
The registration roller pair 44 and the conveyance roller pair are set for a certain period of time based on the timing when the image forming means starts image formation.
46A, 47A and 47B start rotating. The rotation start timing is set so that the recording paper P and the toner image on the photosensitive drum 1 are exactly coincident with each other in the image transfer area.

When the recording paper P plunges into and contacts the transfer drum 5, the recording paper holding sheet film 55S is produced by the corona discharge from the adsorption charger 5C and the action of the adsorption roller 5G.
The particles are electrostatically attracted to the upper side (the attraction roller 5G is normally separated from the transfer drum 5 to reduce the load, and is pressed against the transfer drum 5 only when the recording paper enters). The transfer drum 5 rotates in synchronization with the photosensitive drum 1, and the recording paper P is conveyed to the image transfer area while being held on the transfer drum 5.
Then, the toner image formed on the photosensitive drum 1 by the above-described process is transferred onto the surface of the recording paper by the transfer charger 5B, and then conveyed to the separating portion. Here, since one color image is transferred by one transfer operation, in the case of a single color image, the recording paper P is separated from the transfer drum 5 by an operation described later, but when a multicolor image is formed. Is separated by one rotation without being separated and is conveyed again to the transfer area while being held once on the transfer drum. Then, the next toner image is further transferred onto the previous image, and this process is repeated as many times as necessary (the brush roller 14 and the like are supported so as to be separable from and in contact with the surface of the transfer drum. It is separated from the drum 5).

When the image transfer process is completed, the attraction force between the recording paper P and the recording paper holding sheet film 55S is reduced by the action of the discharging charger 5H at the separating portion, and the subsequent operation of the separating claw 8A and the like is reduced. The recording paper P is separated from the transfer drum 5 by. Specifically, as shown in FIG.
When the leading edge of the recording paper approaches the separation section, the film push-up roller 8
B tries to push the recording paper holding sheet film 55S outward, and the separating claw 8A and the external deformation roller 8C are displaced so as to push the film 55S inward. Then, the curvature of the recording paper holding sheet film 55S locally increases, so that the recording paper P is separated from the film 55S at that position.

Recording paper P separated from the transfer drum 5
Is transported by the transport belt 9C and guided to the nip portion between the fixing roller 9A and the pressure roller 9B via the entrance guide 9D. Then, the heat of the fixing roller 9A fixes the toner image on the surface of the recording paper P. After that, the sheet is conveyed by the pair of sheet discharge rollers 9E and is discharged onto a discharge tray 10 provided outside the apparatus. Finally, the transfer drum 5 is separated from the photosensitive drum 1 to the retracted position, and the driving of the apparatus is stopped.

When performing double-sided recording, the conveyance switching guide 19 is rotated to a predetermined position to guide the recording paper P on which one-sided recording / fixing has been performed to the conveyance vertical path 20, and then the reversing roller 21B via the reversing path 21A. Then, the recording paper P is inverted and conveyed, and is stacked on the intermediate tray 22 via the guide portion 23. Then, after the required number of sheets are stacked, the recording sheets P are sent out one by one from the intermediate tray 22 by the pickup roller 25, merged with the conveying path of the sheet feeding unit 40 by the sheet feeding rollers 26A and 26B, and conveyed to the conveying section 50A. . After that, an image is recorded on the other surface of the recording paper P through the same process. Then, the recording paper P after double-sided recording is discharged to the outside of the apparatus without operating the conveyance switching guide 19.

(Jam Handling Operation) Next, in the printer section described above, it is conceivable that the following conveyance failure of the recording paper P may occur. That is, the registration roller pair 44
When the recording paper P sent out from the recording paper P is attracted onto the transfer drum 5 by the attraction roller 5G, the attraction charger 5C, etc., the leading edge of the recording paper P is caused by the recording paper holding sheet film 55S.
It may not be adsorbed on the surface and may float. When the transfer area is passed in this state, the photosensitive drum 1
The leading edge of the recording paper P is attracted toward the photosensitive drum due to the electrostatic force on the surface. The recording paper P once adsorbed by the rotation of the transfer drum 5 is gradually separated from the transfer drum 5 after passing through the transfer area and is wound around the photosensitive drum 1 side. If the image forming operation is continued as it is, the recording paper P may plunge into the cleaning device 6 and damage the photosensitive drum 1 and the cleaning device 6. Moreover, it becomes very difficult to remove the recording paper P during the jam processing.

Therefore, in order to prevent the above-mentioned situation, in this embodiment, as shown in FIG. 1, the transfer portion jam detecting device 51A is arranged inside the transfer drum 5 immediately below the transfer area. The transfer portion jam detection device 51A optically detects the presence or absence of the recording paper P carried on the surface of the recording paper holding sheet film 55S, whereby the recording paper P is detected at a predetermined timing. When it is not detected, it is determined that the jam is the photosensitive drum winding jam.

Further, as a portion having a risk of jamming similarly to the image transfer area, a separation portion of the recording paper P from the transfer drum 5 can be considered. Therefore, in this embodiment, in addition to the above-described detection device, the separation jam detection device is provided immediately after the separation claw 8A.
51B is provided. The separation jam detecting device 51B mechanically detects the presence or absence of the recording paper P carried on the surface of the recording paper holding sheet film 55S, and when the recording paper P is not detected at a predetermined timing, the separation jam detecting device 51B separates. It is configured to determine that it is a jam.

Hereinafter, the recording paper conveying operation and the jam processing operation when the recording paper P is actually conveyed defectively will be described. As described above, when a jam is detected by the transfer portion jam detecting device 51A or the separation jam detecting device 51B, the leading edge of the recording paper is cleaned by the cleaning device 6 or the brush roller 14.
The photosensitive drum 1 and the transfer drum 5 are immediately stopped in order to prevent the transfer drum 5 from moving to the retracted position at the same time.

When all the operations are stopped here, if the recording paper is continuously fed, as shown in FIG. 6 (the figure shows a case where a separation jam occurs), a jam is generated. It is conceivable that the recording sheet P2, which is being fed next to the sheet P1, stops while straddling the sheet feeding unit 40 and the transfer / transport unit 50. In this case, the transfer / transport unit 50 cannot be pulled out from the main body of the apparatus, and it becomes very difficult to perform the jam processing.

Therefore, in this embodiment, the transfer drum 5
And after the registration roller pair 44 is stopped, the conveyance roller pair 45C on the upstream side of the registration roller pair 44 in the recording paper conveyance direction,
46A, 47A and 47B are rotated for a fixed time. As a result, the recording paper P2 straddling between the paper feed unit 40 and the transfer / transport unit 50 is transported, and the leading edge hits the registration roller pair 44, and the registration roller pair 44
The paper P2 begins to sag between the 44 and the conveyance roller pair 47A, 47B,
The transport guide 48D is largely rotated by the paper strainer, and a space S larger than the normal space S1 (first space) is generated therein.
2 (second space portion) is formed. Then, at least the trailing edge of the recording paper P2 passes through the feeding unit 40, and the transport unit 50A
Until each conveyance roller pair 45C, 46A, 47A, 47
After B is rotationally driven, it is stopped. At this time, the recording paper P
2 is stopped in a state in which the space S2 is greatly curved. After that, the pressure contact between the registration roller pair 44 is released to further retract the suction roller 5G from the transfer roller 5 (this is not an essential operation in this embodiment). Then, a message of recording paper conveyance failure is displayed on the display unit of the apparatus to prompt the user to clear the jam.

When the user recognizes the message on the display, the user opens the front door of the apparatus main body and pulls out the transfer / conveyance unit 50 to the front side. At this time, the leading edge of the jammed paper P1 is slightly moved to the downstream side in the transport direction after the jam is detected (the recording paper P1 is slightly moved from the jam detection until the transportation is completely stopped).
Is moving), but at least brush roller 14 has not been reached. On the other hand, as described above, the trailing edge of the recording paper P2 is stopped inside the transport unit 50A. Therefore, when the transfer / conveyance unit 50 is pulled out, the recording sheet P2 stagnant in the unit 50 is completely pulled out without remaining in the apparatus main body. The user can set the jammed paper P1 on the transfer drum 5.
Peel off and pull up. At this time, since the pressure contact between the registration roller pair 44 and the suction roller 5G is released, even if the trailing edge of the recording paper P1 exists in these portions, the recording paper P1 can be pulled up without causing a load. it can. Further, as shown in FIG. 4, the conveyance roller 47A
Since the conveyance guide 48C is configured to rotate upward and open, the recording paper P2 conveyed next to the jammed paper P1 can be easily removed as shown in FIG.

Here, after the transfer drum 5 and the registration roller pair 44 are stopped, the conveyance roller pairs 45C, 46A, 47A, 47B.
A sequence for driving the will be specifically described. When the separation jam detecting device 51B detects the occurrence of a jam in the separation portion, the transfer drum 5 and the registration roller pair 44 are stopped first, and then the recording paper detection sensor 49A near the entrance of the conveyance portion 50A is checked. And the recording paper detection sensor
When 49A is not blocked (ON state), that is, when there is no recording sheet, the driving of the pair of conveying rollers 45C, 46A, 47A and 47B is immediately stopped. The above-mentioned recording paper detection sensor
When it is detected that the recording sheet P2 is present because 49A is blocked (OFF state), the pair of conveying rollers 45C, 46A, 47
Continue driving without stopping the driving of A and 47B. After that, the recording paper detection sensor 49A is continuously monitored, and the recording paper P2 is detected.
The moment the rear end passes (sensor 49A is OFF → ON)
Then, the driving of the conveying roller pairs 45C, 46A, 47A, 47B is stopped. By doing so, it is possible to avoid a situation in which the recording paper P exists across the feeding unit 40 and the transfer / conveyance unit 50.

The method is not necessarily limited to the above method. For example, a timer is used to measure the time from some reference signal such as the start of operation of the apparatus to calculate the existing position of the recording paper, and as a result, the above-mentioned feeding is performed. When the recording paper P is present at the transitional position between the feeding unit 40 and the transfer / conveyance unit 50, the recording paper P is conveyed into the conveyance section 50A by rotating the conveying roller pair 45C, 46A, 47A, 47B by a necessary amount. The method may be used. In any case, the optimum sequence may be used depending on the device to which the present invention is applied.

Further, as shown in FIG. 7, when the transfer portion jam occurs (when the transfer portion jam detecting device 51A detects the jam), the recording paper P0 in front of the jammed paper P1 is transferred to the transfer conveyance unit 50 and the fixing unit. It is conceivable that the transfer belt 9C and the transfer belt 9 are present (in this embodiment, the transport belt 9C is pulled out together with the transfer transport unit 50, and the inlet guide 9D is left on the apparatus main body side).

Also in this case, the fixing unit 9 is driven independently of the transfer / conveyance unit 50, and after the transfer drum 5 is stopped, the fixing roller pair 9A, 9B is driven to drive the recording paper P0.
By discharging the recording sheet P0, it is possible to eliminate the situation in which the recording sheet P0 exists between the transfer conveyance unit 50 and the fixing unit 9. Here, the transfer portion jam detection device 51A
Since the paper path length between the separation unit and the separation unit is almost the same as the recording sheet interval during continuous sheet feeding, by the time the jam in the transfer unit is detected, the trailing edge of the previously conveyed recording sheet P0 is Almost all the paper is conveyed to the separation section, and there is almost no influence of the suction force from the transfer drum 5. Therefore, even if the fixing roller pair 9A, 9B pulls the recording paper P0, it does not affect the recording paper holding sheet film 55S.

According to the above construction, the portion to be jammed (transfer conveyance unit 50) can be pulled out from the main body of the apparatus, so jamming work such as jam paper removal can be performed easily, reliably and safely. Therefore, the labor of the user can be reduced. In addition, the transfer transport unit
When the 50 is pulled out from the main body of the apparatus, the recording paper which is being conveyed in the apparatus is not broken and remains in the apparatus, and when removing the jammed paper, the recording paper holding sheet film 55S of the transfer drum 5 is deformed or Almost never damaged. Further, there is no risk of scratching the surface of the photosensitive drum as compared with the conventional work of inserting a hand into the apparatus and removing the recording paper. Furthermore, by providing a dedicated recording paper transport space when a jam occurs, it is possible to increase the degree of freedom in design such as shortening the paper path upstream of the registration roller pair 44 in the transport direction (in the normal path). In order to carry out the present invention, it is necessary that at least the paper path length from the entrance of the transport unit 50A to the registration roller pair 44 be equal to or longer than the maximum recording paper length).

[Second Embodiment] Next, another example of the image forming apparatus shown in the first embodiment will be described with reference to FIG.
The present embodiment shows a jam processing sequence that further facilitates the jam processing work. Since the schematic structure of the entire apparatus is the same as that of the first embodiment, the same members are designated by the same reference numerals and the description thereof will be omitted.

The jam processing sequence after the occurrence of the separation jam will be described with reference to FIG. FIG. 8 shows the conveyance state of the recording paper when the separation jam occurs.
This is the same as in FIG. 6 shown in the embodiment. That is, as soon as the separation jam detecting device 51B detects the separation jam, the transfer drum 5 and the registration roller pair 44 are stopped. Here, the difference from the first embodiment is that the conveying roller pair 47A,
47B should be stopped at the same time. Then, the transport unit 50
When the recording paper detection sensor 49A located near the entrance of A determines that the recording paper P2 is present at that position, the other pair of conveyance rollers 45C and 46 are driven to rotate again. At this time, the leading edge of the recording paper P2 hits the nip portion between the pair of transport rollers 47A and 47B, and then the recording paper P2 begins to form a loop. Here, a space S3 is provided between the transport guide 48B and the transport guide 48C. Therefore, the recording paper P formed between the conveying roller pair 46 and the conveying roller pair 47A, 47B.
The second loop bulges upward through the space S3 formed between the guides. Then, the recording paper detection sensor 49
When A detects the trailing edge of the recording paper P2, the above-mentioned conveying roller pair
Stop the driving of 45C and 46 (see the lower part of Fig. 8). At this time,
Since the recording papers P1 and P2 are completely inside the transfer / transport unit 50, the transfer / transport unit 50 can be pulled out without breaking the recording paper P2. The jam handling operation and the recording paper carrying operation thereafter are the same as those in the first embodiment.

According to the above construction, when the transfer / conveyance unit 50 is pulled out, the recording paper P2 can be confirmed on the upper part of the conveyance section 50A, so that it is easy to understand and can be easily removed by utilizing the bulge of the recording paper P2. You can In addition, the recording paper P
As compared with the case where the front end of the second sheet is sent to the pair of registration rollers 44, the recording sheet P2 does not enter the depth of the paper path, so that the recording sheet P2 can be easily pulled out.

In the first and second embodiments described above, the transfer drum 5 and the transfer section 50A are provided in the transfer transfer unit 50.
Although it is equipped with, it is also possible to adopt a configuration in which a fixing unit is added to these. The advantage of this configuration is that the boundary between the portion pulled out from the apparatus main body and the portion remaining in the apparatus main body is between the paper discharge roller pair 9E and the conveyance switching guide 19.
Therefore, when the recording paper P4 exists at this boundary,
The recording paper P4 can be removed by opening the discharge port (left side in FIG. 1) of the apparatus main body to the outside (in the arrow direction). Therefore, the special operation of rotating the fixing roller pair 9A and 9B independently after stopping the transfer drum 5 as described in the first embodiment is not necessary, and the jam processing sequence can be simplified. Therefore, it is possible to further facilitate the user's jam clearance work.

In the first and second embodiments, the transfer drum 5 is used as the conveying means for the recording paper P up to the image forming means, but the present invention is not limited to this. It may be in the form of an endless belt wound around. Further, the jam detection position is not limited to the transfer part and the separation part, and it can be arranged at an appropriate position according to each device. Further, the image forming means is not limited to the electrophotographic method, and any means may be adopted as long as it is an apparatus such as an inkjet method or a thermal transfer recording method, which requires a recording paper conveying mechanism.

[0050]

As described above, in the image forming apparatus according to the present invention, the conveying means, the resist means, and the recording material carrying and conveying means are unitized so that they can be taken out from the apparatus main body. Further, by providing the second space portion for feeding the recording material during the abnormal recording operation, in addition to the first space portion required for transporting the recording material in the normal recording operation, the following effects can be obtained. (1) Since the portion for performing jam processing is unitized and can be pulled out from the main body of the apparatus, jam processing work such as removing jammed paper can be performed easily, reliably and safely, and the labor of the user. Can be reduced. (2) When pulling out the above unit from the main body of the device,
Holds the recording material in the recording material carrying / transporting means (for example, transfer drum) when removing the jammed paper without breaking the recording material such as recording paper that is being conveyed in the apparatus and leaving it in the apparatus. The part is hardly deformed or damaged. (3) There is also no risk of damaging parts of the image forming means (such as the photosensitive drum) as compared with the conventional work of inserting a hand into the apparatus and removing the recording paper. (4) Further, by providing a dedicated recording material conveyance space when a jam occurs, it is possible to increase the degree of freedom in design such as shortening the conveyance path upstream of the registration roller means in the conveyance direction.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing a schematic configuration of a copying machine.

FIG. 2 is an explanatory diagram illustrating a transport unit of the copying machine.

FIG. 3 is an explanatory diagram of a transfer drum.

FIG. 4 is an explanatory diagram showing a configuration of a transfer / transport unit.

FIG. 5 is an explanatory diagram showing a separating operation of the transfer drum.

FIG. 6 is an explanatory diagram showing the operations of the paper feed unit and the transport unit when a separation jam occurs.

FIG. 7 is an explanatory diagram showing an operation of the fixing unit when a transfer portion jam occurs.

FIG. 8 is an explanatory diagram showing the operations of the paper feed unit and the transport unit when a separation jam occurs according to the second embodiment.

FIG. 9 is an explanatory diagram showing a configuration of a conventional copying machine.

[Explanation of symbols]

 P ... Recording paper 1 ... Photosensitive drum 2 ... Primary charger 3 ... Exposure optical system 3A ... Polygon mirror 3B, 33 ... Lens 4 ... Developing device 5 ... Transfer drum 5B ... Transfer charger 5C ... Adsorption charger 5D, 5E ... Charger for film static elimination 5G ... Adsorption roller 5H ... Charger for static elimination 6 ... Cleaning device 8A ... Separation claw 8B ... Roller for pushing up film 8C ... Roller for external deformation 9 ... Fixing unit 9A ... Fixing roller 9B ... Pressure roller 9C ... Conveying Belt 9D ... Entrance guide 9E ... Ejection roller pair 10 ... Ejection tray 11 ... Pre-exposure lamp 12 ... Potential sensor 13 ... Drum light amount detection means 14 ... Brush roller 15 ... Brush type static eliminator 16 ... Oil removal roller 17 ... Backup brush 19 … Conveying path switching guide 20… Conveying vertical path 21A… Reversing path 21B… Reversing roller 22… Intermediate tray 23… Guide section 25, 42… Pickup row 26A, 26B, 43A, 43B ... Paper feeding roller 30 ... Original 31 ... Original platen glass 32 ... Exposure lamp 34 ... Full color sensor 40 ... Paper feeding unit 41 ... Cassette 44 ... Registration roller pair 45A, 45B, 45C, 46 ... Conveying rollers Pair 47A, 47B ... Conveying rollers 48A, 48B, 48C, 48D, 48E ... Conveying guides 48F, 48G ... Adsorption guides 49A, 49C ... Recording paper detection sensor 50 ... Transfer conveying unit 50A ... Conveying section 50F ... Unit front plate 50R ... Unit Rear plate 50P ... Positioning shaft 50S ... Stay shaft 51A ... Transfer part jam detection device 51B ... Separation jam detection device 55A ... Annular member 55B ... Connection member 55F ... Frame 55S ... Recording paper holding sheet film 62A, 62B ... Slider 70F ... Front plate 70FP ... Groove 70R ... Rear plate 70RP ... Hole 71 ... Cam 72 ... Cam shaft

Claims (3)

[Claims] 1. A feeding means for feeding a recording material, a conveying means for conveying the recording material fed by the feeding means, and correcting skew of the recording material. At the same time, a registration means for carrying the image in synchronization with the recorded image, an image forming means for forming an image on the recording material according to image information, and an image forming means for carrying the recording material to the image forming means. The recording material carrying and conveying means for carrying the recording material, and the conveying means, the resist means, and the recording material carrying and conveying means are unitized and can be taken out from the apparatus main body, and the normal recording is performed on a part of the conveying means. An image forming apparatus characterized in that a second space portion for feeding the recording material during an abnormal recording operation is provided in addition to the first space portion required for transporting the recording material in the operation. 2. The conveyance means and the registration means are independently driven, and when the recording material is jammed, the conveyance means is driven while the registration means is stopped. The image forming apparatus according to claim 1, wherein: 3. A detection means for detecting the presence or absence of a recording material is provided in the vicinity of an area separating the feeding means and the conveying means, and the detection means detects the recording material when a jam occurs. The image forming apparatus according to claim 1, wherein the conveying means conveys the recording material until the trailing edge of the recording material passes through the detecting means.